i2c-algo-bit: Emulate SMBus block read

Now that i2c-core lets the i2c bus drivers emulate the SMBus block read
and SMBus block process call transaction types, let's implement that in
the popular i2c bit-banging driver. This will also act as a reference
implementation for other bus drivers which want to do the same.

Signed-off-by: Jean Delvare <khali@linux-fr.org>

diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
index 28b7e25ca79c89889bbf42f1c4fb4a880a83bcca..fcef6ff3d2878eaf3180a4c8345401c860628d82 100644 (file)
--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -391,6 +391,21 @@ static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
                };
                scllo(adap);
                sdahi(adap);
+
+               /* Some SMBus transactions require that we receive the
+                  transaction length as the first read byte. */
+               if (rdcount == 1 && (msg->flags & I2C_M_RECV_LEN)) {
+                       if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) {
+                               printk(KERN_ERR "i2c-algo-bit: readbytes: "
+                                      "invalid block length (%d)\n", inval);
+                               return -EREMOTEIO;
+                       }
+                       /* The original count value accounts for the extra
+                          bytes, that is, either 1 for a regular transaction,
+                          or 2 for a PEC transaction. */
+                       count += inval;
+                       msg->len += inval;
+               }
        }
        return rdcount;
 }
@@ -509,6 +524,8 @@ bailout:
 static u32 bit_func(struct i2c_adapter *adap)
 {
        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | 
+              I2C_FUNC_SMBUS_READ_BLOCK_DATA |
+              I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
               I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
 }